Solid serous adenoma of the pancreas: a rare variant within the family of pancreatic serous cystic neoplasms.

We report the third case of a solid serous adenoma of the pancreas, a rare variant of tumor within the family of pancreatic serous cystic neoplasms. This asymptomatic tumor presented in a 66-year-old man during imaging for another problem. Computed tomography of the abdomen demonstrated a 3.5-cm hypervascular mass in the head of the pancreas. A pylorus preserving pancreaticoduodenectomy was performed. Histological examination demonstrated a neoplasm identical to a serous cystadenoma-glycogen-rich cuboidal or polygonal cells with finely granulated eosinophilic or clear cytoplasm. More often, the neoplasm contained solid areas and tubules but no microcysts. Periodic acid Schiff's-glycogen staining was positive in some cells, turning negative after diastase was applied. Immunostaining was positive for CK7, CK8, neuron specific enolase, and MUC6. The microscopic findings of a solid neoplasm of cuboidal cells rich in glycogen and the immunostaining listed associate this tumor with the previously 2 reported cases of solid serous adenoma. All 3 reported cases thus far have proven to be benign lesions by pathological examination. Because clinical follow-up is reported only in the present case, caution should be exercised in declaring the solid serous adenoma of the pancreas as a benign lesion.